1. Field of the Invention
The present invention relates to a target device such as a digital television receiver to be connected to IEEE 1394 serial bus.
2. Description of the Related Art
A hard disk recorder is known which is connected to a controller device such as a set-top box or a digital television receiver using an IEEE 1394 serial bus cable, and which is controlled by an IEEE 1394 control command, called AV/C (Audio and Video Control) command, sent from the controller device. This HDD is an AV (Audio Video) device, and also called AVHDD (Audio Video Hard Disk Drive). The AV/C command is designed to achieve desired functions of AV devices with minimum necessary means in the AV devices so that the necessary means can be mounted even on AV devices having a simple structure. Thus, the AV/C command fits well with AV devices such as HDDs, so that demand for the AVHDD using the AV/C command is expected to increase than before.
However, the AVHDD has the problem that it is more expensive than an HDD of the type which is generally connected to a personal computer by a USB (Universal Serial Bus) cable. This problem can be solved if the HDD of the type which is connected by a general USB cable can function as a disk subunit (hypothetical functional unit having a function as a disk device) on an IEEE 1394 network, which makes it possible to reduce the total cost of the IEEE 1394 network system.